CVE-2000-0258: Input Validation
IIS 4.0 and 5.0 allows remote attackers to cause a denial of service by sending many URLs with a large number of escaped characters, aka the "Myriad Escaped Characters" Vulnerability.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
Restrict external access to affected Microsoft Internet Information Services (IIS 4.0 and 5.0) hosts at the network perimeter using firewall rules or ACLs. Deploy a WAF or reverse proxy to detect and block or drop requests that contain an excessive number of percent-encoded (escaped) characters and to rate-limit requests per client to mitigate denial-of-service attempts.
- Operational
Monitor IIS logs for large volumes of requests containing many escaped (percent-encoded) characters. When detected, block or throttle offending source IPs, isolate affected hosts as needed, and follow incident response procedures (including restarting IIS if required). Subscribe to vendor/security advisories and apply any vendor-supplied patches or upgrades for IIS 4.0/5.0 when they become available.
Event History
Frequently Asked Questions
What is the severity of CVE-2000-0258?
CVE-2000-0258 is classified as a denial of service vulnerability affecting IIS 4.0 and 5.0.
How do I fix CVE-2000-0258?
To mitigate CVE-2000-0258, it is recommended to upgrade to a newer version of IIS that is not vulnerable to this issue.
What software versions are affected by CVE-2000-0258?
CVE-2000-0258 affects Microsoft Internet Information Server 4.0 and Internet Information Services 5.0.
Can CVE-2000-0258 lead to server downtime?
Yes, CVE-2000-0258 can lead to server downtime by causing denial of service through excessive requests.
Is there any workaround for CVE-2000-0258?
There are no known workarounds for CVE-2000-0258 other than updating the affected software.